Many of the new EFI systems will auto-tune (even the $180 Megasquirt). Basically you use a wideband oxygen sensor, load the table in your EFI system with your desired A/F ratio all over the RPM/load map, and the O2 sensor takes it from there. The only problem is as the O2 sensors age, they get less accurate. But something tells me they can afford an $80 sensor every now and then.